1251875Speter/* Licensed to the Apache Software Foundation (ASF) under one or more 2251875Speter * contributor license agreements. See the NOTICE file distributed with 3251875Speter * this work for additional information regarding copyright ownership. 4251875Speter * The ASF licenses this file to You under the Apache License, Version 2.0 5251875Speter * (the "License"); you may not use this file except in compliance with 6251875Speter * the License. You may obtain a copy of the License at 7251875Speter * 8251875Speter * http://www.apache.org/licenses/LICENSE-2.0 9251875Speter * 10251875Speter * Unless required by applicable law or agreed to in writing, software 11251875Speter * distributed under the License is distributed on an "AS IS" BASIS, 12251875Speter * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13251875Speter * See the License for the specific language governing permissions and 14251875Speter * limitations under the License. 15251875Speter */ 16251875Speter 17251875Speter#ifndef APR_GLOBAL_MUTEX_H 18251875Speter#define APR_GLOBAL_MUTEX_H 19251875Speter 20251875Speter/** 21251875Speter * @file apr_global_mutex.h 22251875Speter * @brief APR Global Locking Routines 23251875Speter */ 24251875Speter 25251875Speter#include "apr.h" 26251875Speter#include "apr_proc_mutex.h" /* only for apr_lockmech_e */ 27251875Speter#include "apr_pools.h" 28251875Speter#include "apr_errno.h" 29251875Speter#if APR_PROC_MUTEX_IS_GLOBAL 30251875Speter#include "apr_proc_mutex.h" 31251875Speter#endif 32251875Speter 33251875Speter#ifdef __cplusplus 34251875Speterextern "C" { 35251875Speter#endif /* __cplusplus */ 36251875Speter 37251875Speter/** 38251875Speter * @defgroup APR_GlobalMutex Global Locking Routines 39251875Speter * @ingroup APR 40251875Speter * @{ 41251875Speter */ 42251875Speter 43251875Speter#if !APR_PROC_MUTEX_IS_GLOBAL || defined(DOXYGEN) 44251875Speter 45251875Speter/** Opaque global mutex structure. */ 46251875Spetertypedef struct apr_global_mutex_t apr_global_mutex_t; 47251875Speter 48251875Speter/* Function definitions */ 49251875Speter 50251875Speter/** 51251875Speter * Create and initialize a mutex that can be used to synchronize both 52251875Speter * processes and threads. Note: There is considerable overhead in using 53251875Speter * this API if only cross-process or cross-thread mutual exclusion is 54251875Speter * required. See apr_proc_mutex.h and apr_thread_mutex.h for more 55251875Speter * specialized lock routines. 56251875Speter * @param mutex the memory address where the newly created mutex will be 57251875Speter * stored. 58251875Speter * @param fname A file name to use if the lock mechanism requires one. This 59251875Speter * argument should always be provided. The lock code itself will 60251875Speter * determine if it should be used. 61251875Speter * @param mech The mechanism to use for the interprocess lock, if any; one of 62251875Speter * <PRE> 63251875Speter * APR_LOCK_FCNTL 64251875Speter * APR_LOCK_FLOCK 65251875Speter * APR_LOCK_SYSVSEM 66251875Speter * APR_LOCK_POSIXSEM 67251875Speter * APR_LOCK_PROC_PTHREAD 68251875Speter * APR_LOCK_DEFAULT pick the default mechanism for the platform 69251875Speter * </PRE> 70251875Speter * @param pool the pool from which to allocate the mutex. 71251875Speter * @warning Check APR_HAS_foo_SERIALIZE defines to see if the platform supports 72251875Speter * APR_LOCK_foo. Only APR_LOCK_DEFAULT is portable. 73251875Speter */ 74251875SpeterAPR_DECLARE(apr_status_t) apr_global_mutex_create(apr_global_mutex_t **mutex, 75251875Speter const char *fname, 76251875Speter apr_lockmech_e mech, 77251875Speter apr_pool_t *pool); 78251875Speter 79251875Speter/** 80251875Speter * Re-open a mutex in a child process. 81251875Speter * @param mutex The newly re-opened mutex structure. 82251875Speter * @param fname A file name to use if the mutex mechanism requires one. This 83251875Speter * argument should always be provided. The mutex code itself will 84251875Speter * determine if it should be used. This filename should be the 85251875Speter * same one that was passed to apr_global_mutex_create(). 86251875Speter * @param pool The pool to operate on. 87251875Speter * @remark This function must be called to maintain portability, even 88251875Speter * if the underlying lock mechanism does not require it. 89251875Speter */ 90251875SpeterAPR_DECLARE(apr_status_t) apr_global_mutex_child_init( 91251875Speter apr_global_mutex_t **mutex, 92251875Speter const char *fname, 93251875Speter apr_pool_t *pool); 94251875Speter 95251875Speter/** 96251875Speter * Acquire the lock for the given mutex. If the mutex is already locked, 97251875Speter * the current thread will be put to sleep until the lock becomes available. 98251875Speter * @param mutex the mutex on which to acquire the lock. 99251875Speter */ 100251875SpeterAPR_DECLARE(apr_status_t) apr_global_mutex_lock(apr_global_mutex_t *mutex); 101251875Speter 102251875Speter/** 103251875Speter * Attempt to acquire the lock for the given mutex. If the mutex has already 104251875Speter * been acquired, the call returns immediately with APR_EBUSY. Note: it 105251875Speter * is important that the APR_STATUS_IS_EBUSY(s) macro be used to determine 106251875Speter * if the return value was APR_EBUSY, for portability reasons. 107251875Speter * @param mutex the mutex on which to attempt the lock acquiring. 108251875Speter */ 109251875SpeterAPR_DECLARE(apr_status_t) apr_global_mutex_trylock(apr_global_mutex_t *mutex); 110251875Speter 111251875Speter/** 112251875Speter * Release the lock for the given mutex. 113251875Speter * @param mutex the mutex from which to release the lock. 114251875Speter */ 115251875SpeterAPR_DECLARE(apr_status_t) apr_global_mutex_unlock(apr_global_mutex_t *mutex); 116251875Speter 117251875Speter/** 118251875Speter * Destroy the mutex and free the memory associated with the lock. 119251875Speter * @param mutex the mutex to destroy. 120251875Speter */ 121251875SpeterAPR_DECLARE(apr_status_t) apr_global_mutex_destroy(apr_global_mutex_t *mutex); 122251875Speter 123251875Speter/** 124251875Speter * Return the name of the lockfile for the mutex, or NULL 125251875Speter * if the mutex doesn't use a lock file 126251875Speter */ 127251875SpeterAPR_DECLARE(const char *) apr_global_mutex_lockfile(apr_global_mutex_t *mutex); 128251875Speter 129251875Speter/** 130251875Speter * Display the name of the mutex, as it relates to the actual method used 131251875Speter * for the underlying apr_proc_mutex_t, if any. NULL is returned if 132251875Speter * there is no underlying apr_proc_mutex_t. 133251875Speter * @param mutex the name of the mutex 134251875Speter */ 135251875SpeterAPR_DECLARE(const char *) apr_global_mutex_name(apr_global_mutex_t *mutex); 136251875Speter 137251875Speter/** 138251875Speter * Get the pool used by this global_mutex. 139251875Speter * @return apr_pool_t the pool 140251875Speter */ 141251875SpeterAPR_POOL_DECLARE_ACCESSOR(global_mutex); 142251875Speter 143251875Speter#else /* APR_PROC_MUTEX_IS_GLOBAL */ 144251875Speter 145251875Speter/* Some platforms [e.g. Win32] have cross process locks that are truly 146251875Speter * global locks, since there isn't the concept of cross-process locks. 147251875Speter * Define these platforms in terms of an apr_proc_mutex_t. 148251875Speter */ 149251875Speter 150251875Speter#define apr_global_mutex_t apr_proc_mutex_t 151251875Speter#define apr_global_mutex_create apr_proc_mutex_create 152251875Speter#define apr_global_mutex_child_init apr_proc_mutex_child_init 153251875Speter#define apr_global_mutex_lock apr_proc_mutex_lock 154251875Speter#define apr_global_mutex_trylock apr_proc_mutex_trylock 155251875Speter#define apr_global_mutex_unlock apr_proc_mutex_unlock 156251875Speter#define apr_global_mutex_destroy apr_proc_mutex_destroy 157251875Speter#define apr_global_mutex_lockfile apr_proc_mutex_lockfile 158251875Speter#define apr_global_mutex_name apr_proc_mutex_name 159251875Speter#define apr_global_mutex_pool_get apr_proc_mutex_pool_get 160251875Speter 161251875Speter#endif 162251875Speter 163251875Speter/** @} */ 164251875Speter 165251875Speter#ifdef __cplusplus 166251875Speter} 167251875Speter#endif 168251875Speter 169251875Speter#endif /* ndef APR_GLOBAL_MUTEX_H */ 170